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authorLars Knoll <lars.knoll@nokia.com>2009-03-23 09:34:13 (GMT)
committerSimon Hausmann <simon.hausmann@nokia.com>2009-03-23 09:34:13 (GMT)
commit67ad0519fd165acee4a4d2a94fa502e9e4847bd0 (patch)
tree1dbf50b3dff8d5ca7e9344733968c72704eb15ff /src/3rdparty/webkit/JavaScriptCore/wtf/RandomNumber.cpp
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Long live Qt!
Diffstat (limited to 'src/3rdparty/webkit/JavaScriptCore/wtf/RandomNumber.cpp')
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diff --git a/src/3rdparty/webkit/JavaScriptCore/wtf/RandomNumber.cpp b/src/3rdparty/webkit/JavaScriptCore/wtf/RandomNumber.cpp
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+/*
+ * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
+ * (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "RandomNumber.h"
+
+#include "RandomNumberSeed.h"
+
+#include <limits>
+#include <limits.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+namespace WTF {
+
+double randomNumber()
+{
+#if !ENABLE(JSC_MULTIPLE_THREADS)
+ static bool s_initialized = false;
+ if (!s_initialized) {
+ initializeRandomNumberGenerator();
+ s_initialized = true;
+ }
+#endif
+
+ uint32_t part1;
+ uint32_t part2;
+ uint64_t fullRandom;
+#if COMPILER(MSVC) && defined(_CRT_RAND_S)
+ rand_s(&part1);
+ rand_s(&part2);
+ fullRandom = part1;
+ fullRandom <<= 32;
+ fullRandom |= part2;
+#elif PLATFORM(DARWIN)
+ part1 = arc4random();
+ part2 = arc4random();
+ fullRandom = part1;
+ fullRandom <<= 32;
+ fullRandom |= part2;
+#elif PLATFORM(UNIX)
+ part1 = random() & (RAND_MAX - 1);
+ part2 = random() & (RAND_MAX - 1);
+ // random only provides 31 bits
+ fullRandom = part1;
+ fullRandom <<= 31;
+ fullRandom |= part2;
+#else
+ part1 = rand() & (RAND_MAX - 1);
+ part2 = rand() & (RAND_MAX - 1);
+ // rand only provides 31 bits, and the low order bits of that aren't very random
+ // so we take the high 26 bits of part 1, and the high 27 bits of part2.
+ part1 >>= 5; // drop the low 5 bits
+ part2 >>= 4; // drop the low 4 bits
+ fullRandom = part1;
+ fullRandom <<= 27;
+ fullRandom |= part2;
+#endif
+ // Mask off the low 53bits
+ fullRandom &= (1LL << 53) - 1;
+ return static_cast<double>(fullRandom)/static_cast<double>(1LL << 53);
+}
+
+}